Physiology of Eating - L8

1. U-shaped curve for the relationship between birth weight and adult metabolic disease -> born small have an increased risk of obesity later in life

2. undereweight: intrauterine growth retardation -> enhanced survival and catch-up growth

3. overweight: macrosomic/increased body fat -> normal/increased food availability, high fat/caloric diet 

1. DNA methylation is very dynamic during embryogenesis

2. happens in response to many factors, including in utero nutrition -> may permanently alter offspring gene expression 

3. gestational under- and overnutrition leads to hypomethylation of IGF2 gene

4. increased expression of IGF2 leads to increased growth of tissues 

insulin also plays a role in protein metabolism -> to high amount of protein in the diet is associated with risk of obesity

1. culture: we are getting used to like what we eat 

2. sweet taste receptors: 1 receptor for many sweet substances

3. bitter receptor: widely expressed throughout the body -> mediate diverse non-tasting roles 

4. genetic differences (polymorphisms) in receptors also account for individual differences 

1. at age 18 months

2. = rejection of foods that are novel or unknown to the child

3. evolutionary beneficial mechanism: help children avoid ingesting noxious of toxic chemicals (happens primarily in the visual domain)

4. children prefer the food they know (safety) -> new + potentially harmful food is avoided 

1. poeple learn to like what they're used to eat -> repeated exposure increases liking and intake

1. while eating the same food, the palatability decreases 

2. promotes switching among nutrient sources & hence increased chance of balanced nutrition 

1. prenatal conditioning to liking foods does happen -> pre- and postnatal eating behavior of mothers does influence childs eating behavior postnatally -> leads to imprinting of preferences

2. children usually like the taste impresions they discovered during pregnancy & nursing later in life 

3. taste of BM is much more variable than taste of formula -> BF children have less neophobia & lower obesity risk